Continuous flow nut cracking apparatus



April 18, 1950 F. M. BALDWIN CONTINUOUS FLOW NUT CRACKING APPARATUS Filed Aug. 25, 1945 2 Sheets-Sheet 1 HIS ATTORNEYS;

April 18A, 1950 F. M BALDWlN 2,504,374

CONTINUOUS FLOW NUT -CRACKING APPARATUS INVENTOR. FREDE RICK M. BALDWIN lBY @l/aww V HIS ATTORNEYS.

Patented Apr. 18, 1950 iIN I TED STATES' fir A'EENT FFICE CONTINUOUS FLOW NUT -CRACKING v APPARATUS This invention relates to mechanism for crack-- ing the Ashells of nuts so as to effect separation of the ynut meat from the shells.

An object lof the invention is to provide mechanism of the character described which is adapted to operate upon and efficiently crack ungraded nuts embracing a Wide `.range of sizes.

Another object .of the Vinvention is to provide apparatus lof the nature referred to which effects 1a considerable increase in the output of large-'size `nut meat pieces and consequently lessons the percentage of minced meat which has very :low commercial value.

A further obje-ct of the linvention is to provide nut shelling apparatus which is capable of handl'm'gan increased Volume of `nuts due to the high speed operational features Vincorporated in the mechanism. v

Still another object of the invention Vis to pro--V vide, in a tnut vshelling apparatus, resilient Vshell cracking .elements which produce a gentle but positive crushing strain on Athe shells without materially damaging the `nut meat.

Yet another object of the invention is to provide, in a 'nut Vshelling apparatus, means for simultaneously "and rindepenolently imposing crushing pressure on the `nut in a plurality of unrelated planes vso as to effect a thorough crack-ing of the 'shellin order to more readily facilitate its separation ,from the `nut meat.

.A still further object of the invention is to provide -a fcombinednut grader 'and shelling rapparatus.

Other objects and features of value will becomeapparent as the detailed description of the invention, hereunto annexed, proceeds. It is to be understood 'that the invention Vis not to be limited to the speci-flciorm thereof herein shown and :described as lvarious rother l embodiments thereof maybe employed within the scope of the appended claims. l

Referring to .thedraw-ings:

Figure l is a side elevational View of the 4nut shelling apparatus of. my invention.

Figure l2 is a-:iragmental side elevational View showing ya modiiiecl `formof drive for the rotors.

Figure 3 is a top plan view, to van enlarged scale, of .a set kof rotors and its associated .screening and trans-ferrollers.

Eigure 4 isa vertical sectional view of the rotor structure, the plane `oi" section being indii cated Vby the lineA- of Figure 3.

VFigure .5 is a vertical sectional view showin the operational face of one of the rotor disks. The plane in which .the view is taken is indicated by the line '5-5 of Figure 4.

4 Claims. (Cl. 14S-11) Figure .6 is a, fragmental horizontal Asectional view, to an enlarged scale, showing the relationship between opposed pairs of rotor disks in a set thereof. The plane in which the view is taken is indicated by the line 5 5 of Figure '1.

Figure `7 is a top plan view of the rotor oscillator cam.

Figure 8 is a vertical sectional View showing the cam of Figure 7 `in its operational position. The plane in which the view is taken is indicated 'by the 'line 8-8 of Figure 4.

Ina previous type'of nut shelling machine, the nuts were fed between a pair of tangentially disposed semi-circular rot-ors each of which was provided with a peripheral groove vso as to form between the rotors, in their mutual plane of tangency, a cylindrical passage through which the nuts were forced by oscillating motion imparted to the rotors thereby effecting suiiicient cracking of the shells -to permit separation of the latter from the nut meat. Obviously, since the rotors were rigid :only nuts which-were slightly larger than the aforesaid cylindrical passage would be crack-ed upon being passed between the rotors while those which were smaller `or .lmateria-lly larger would either drop freely through the passage 4or would be crushed so severely that the nut meat was render-ed commercially .undesirable. Further-more, after being lin use `for some time, the rotor grooves would become `coated with nut oil from the crushed meats, which Wouldreduce the fricti-onal grip on the nut shells thereby causing slippage which materially re-` duced the output of the machine, In addition. since the .rotors were adjusted to operate onlyon a Acertain vsize of nut it was necessary to either grade4 the nuts into batches of the various .sizes and to run each batch independently through the machine, with .compensating adjustments of therotorsbetween runs, or to provide a plurality of machines each ixedly adjusted to accept only a prescribed size of nut. Operating under normal conditions the above machine was capable of producing only Yabout 48 per cent of half kernels, the remainder being `divided about as follows: 18 per cent about one-fourth kernel, about `7 per cent smaller than one-fourth kernel, about 2 2 percent split in half but lremaining in the shell and about 5 percent of small particles or minced meat. In addition to the cracked nuts there were always about 25 lpercent of uncracked nuts, mostly abnormally under-sized, in the tailings that had to be gathered and re--run through the machine after properly adjusting the latter.

The apparatus of the present invent-ionovercomes the undesirable features Youtlined above 3 and vastly improves the quality of work done over the old type machine while greatly increasing the input capacity and product output of the mechanism. There is now no need for segregating the nuts into separate batches as the machine is capable of eiiciently cracking all of the nuts within a comparatively wide range of normal sizes since one of the important operational characteristics of the machine is its capability of receiving a continuous flow of the ungraded nuts, selecting and cracking the larger of the nuts and passing the remainder on to successive stages of the mechanism wherein further selections of larger nuts are accomplished until substantially all of the nuts are cracked. The actual cracking of the nut shells is done by mechanism which is superior to the apparatus previously employed in that the resilient nature of the mechanism permits of a certain amount of leeway in the size of nut receivable by the mechanism and its improved design eliminates the above-mentioned undesirable fouling caused by the nut oil.

In greater detail, the apparatus comprises a suitable supporting structure having a framework 9 on which a pair of spaced parallel side plates I I is secured. Mounted on what may aptly be termed the front of the machine is a continuous feed conveyor comprising a materialreceiving hopper I2 formed integrally with and at the bottom of a trunk I3 rising angularly upwardly and rearwardly toward the top of the machine and terminating in a downwardly opening discharge port I4. Shafts I6 and VI, positioned respectively adjacent upper and lower ends of the trunk I3 and journaled in suitable bearings provided in the sides of the conveyor housing, carry sprockets I8 and I9 with which chains are engaged carrying an endless belt 2i fitted with cleats or plates 22. The arrangement of the parts is such that nuts deposited in the hopper I2 are engaged by the cleats or plates 22 and are carried upwardly through the trunk I3 to be discharged through the port I4. rlhe elevation of the discharge port I4 of the conveyor is sufficient so that the subsequent flow of the nuts through the various units of the apparatus to be hereinafter described is accomplished by the force of gravity.

Means is provided for driving the conveyor just described. Suitably mounted on a supporting frame 23, secured to and forming part of the framework 9, is a motor 24 equipped with a pulley 26 driving, through a belt 21, a pulley 28 flXed on and for rotation with a shaft 2E! jour* naled in suitable bearings 3I the top and to the rear of the framework. The shaft 29 carries a pinion 32 meshing with a gear 33, carried on a shaft 34 which is journaled in suitable bearings 36 also mounted on the framework, the shaft 34 being equipped with a pulley 31 which drives, through a belt 38 and pulley 39, a jack-shaft 4I journaled in bearings provided therefor in the side plates II. A small pulley 42, engaged by an endless belt 43, drives a comparatively larger pulley 44 secured on the shaft I'I located at the lower end of the conveyor. The speed ratios between the various interconnected components of the drive is such that the most efficient linear speed is imparted to the conveyor so that the latter will neither feed material in overabundance, so that clogging of the machine will occur, nor at such a reduced rate that the output capabilities of the machine will be adversely affected.

. Means are provided for selecting certain f mounted at the nuts discharged from the port I4 and for cracking the shells thereof. Disposed immediate- 1y below the discharge port is a plurality of cracker units generally designated by the numerals 46, yIl'I, and 48. It may be stated here that although three units have been herein chosen as a means of explaining the invention and its mode of operation a larger or lesser number of the units may be employed depending upon the overall range of the relative sizes between the nuts to be operated upon. Each of the cracker units comprises an enclosed chamber 49 having an inlet hopper 5I formed in the top thereof which is provided with a central discharge aperture 52 disposed immediately above a pair of horizontally spaced cracker rotors, generally indicated by the numeral 53, the said aperture 52 being in vertical alignment with the plane of tangency between the rotors. Each of the chambers 49 is also provided in its bottom with a discharge opening 54.

Each oi the cracker rotors, as is best shown in Figure 4 comprises a drive shaft 56 which is journaled in suitable bearings 5'! carried by the side plates I I or any other convenient portion of the apparatus framework 9. Mounted on the shaft 5B is a plurality, preferably four, of cracker disks 53 each of which is provided with a centrally bored hub 59 through which the shaft 56 passes, an elongated key 6I mounted in a keyway 62 on the shaft being provided which connects each of the disks 58 for rotation with the shaft. Each of the disks, as shown in Figures 4 and 5 is composed of light steel plate, a thickness of about three-sixteenths of an inch having been found to produce satisfactory results, and arranged in successive order about a circular path adjacent the periphery of each disk is a plurality of resilient ngers 63 each of which is formed by shearing narrow portions from the parent material of the disk. Each finger is shaped, as illustrated in Figure 6, to form, substantially, a quadrant of a circle designed to encompass the periphery of the chosen size of nut to be cracked. It may be stated here that each of the cracker units 46, 47 and 48 is designed to accommodate a certain range of nut sizes, the uppermost unit being capable of handling a limited group of larger nuts, the next lower unit handling nuts ranging smaller in size than the smallest nut of the preceding group, and so forth until the entire normal range of nut sizes is covered. The group of disks 58 on each shaft 56 is arranged in pairs, the disks of each pair being in confronting relationship, with the fingers 63 extending toward each other. This provides the effect of a sem'icircular peripheral groove in each pair of disks forming a rotor unit and, as will be seen in Figure 6, when two radially spaced rotors are positioned in tangential relationship, as occurs in each of the chambers 49, a circular orifice 64 is formed by fingers 63 of the respective disks, through which the nuts, dropping through the apertures 52 from the hopper 5I above are passed.

Means are provided for imparting to the respective shafts 56 a rotary motion so that as the nuts drop from the hoppers 5I into the rotor grooves, the larger of the nuts will be forced, by the tractive effort of the fingers 53 against the shells thereof, through the aperture 64 so as to effect rupturing of the shell. This particular pressure which is imposed in the direction of the rotor diameter may aptly be termed a radial rupturing pressure as distinguished from an axial rupturing pressure which will be presently described.. There are two possible ways of the drive for :rotors dependingnponwhether a reciprocatingsmotion desired for 'Whether full and Icontinued rotation of the Yrotors is to be in'ovided rEach `drive has .its desirable features., the iormerperhapsbei-ng themostattractive due to .its simplicity. However', the principal drawback associated with the reciprocating vdrive :is the loss of :productive :new in the machine fduring recovery movement ofthe rotors but this'm'ay be mferconie to'some extent by speeding the machine. in fl-etsii, 'the reciprocating drive com-V prises .levers secured to :each .of :the shafts l56, these `.levers "being inter-.connected in separate groups by connecting rods' 61 in :order that :the shafts so interconnected may be synchronously moved. A shaft S8, which is 'journaied infsuitable bearings `in the respective zsideplat-es :I l oarries apuiley-'e connecte-d hy a'belt .ll Witha pul-V ley,7 l2 mounted .on the jack-shattdlt and also is `prmided with a `pinion 13fwhich lmeshes#with a geen l carrled'by a :shaft 'lljournaled vin the manner of the TGS. The shafft f6 also {carries, at its respective ends, `disks H each oi 4which is 'provided with a radiaiiyI-oset crank stud "it which received one end of a link 19, the .other end ont the latter heing lpivo'tally connected with an end ofthe connecting rods?. 'Energiaation of the drive apparatus above described wilt-cause rotationo the'ldls'ks "H and 'aV resulting reciprocaton .ci the connecting rods ii determined `by the orbit diameter ofthe crank pins'l thus'rock# ing the rotors in successive reversalsof Irotary motion.

nFigure 2 sustained unidirectional rotation of the rotors. Inthis inodication, each of the shafts 56 is provided with work gears Si which mesh Withworms 82 -carriedby a drive shaft 83 which may be connected conventional `manner with and to be driven hy the inotor'Ed. In this drive the worms 8-2 are, respectively, `right andleft hand as are their mating Vgears 8i so that'relatively reversed rotationai movement will obtain between't-herotors of ea-ch cracker unit so that the nuts flowing p' ont of 'the Vhoppcrs 5^! will be tractiona-lly'drawn downwardly between the rotors andthrough 'the apertures E4 formed thereby.

rWhen, in the Ycourseoithe now ofnuts from the hoppersil, a nut possessing a larger diametrical dimension than the .size oi vthe'aprertiu'e l'6'4 is encountered it will be pulled, due tothe tractive ei'fort of the 'fingers t3 against its shell, through the aperture thereby causing pressure to be exerted 'on the shell by the ngers'l ysuicient to rupture the shell. Conversely, 'nuts smaller than aperture St vwill pass therethrough without )being subjected to any crushing strain. The above crushing stress sinceit is applied in a direction radially ofthe rotors may, for .purposes of .this description, be termed radial stress as distinguished'from an' "axial stress Valso imposed .on the nut'in a manner to be explained presently.

"Means areprovidedfor adjustably varying the sizeof the :aperturet so as to govern the minimum size of nut to `loe .cracked ...by aparticular cracking unit. InFigure 4 .it `will be notedthat each of the rotor disks is :capable sliding motion axially `of the shaft- 56 and that thehubs `59 carry studs S4 which pass freely through Aaperture t5 formed Ain collars 8l which are -xedly-secured to the shaft by pins or setscrews 8B or in any other suitable manner. Nuts .89, in threaded engagiement with the studs 8d serve to secure the position of-ythe disks 58 relative V`to the collars kl8l. `Asshownone `method of effecting member such as the bearing 51;

6 summa-for purposes `of description, that the positions ci vthe two center disks-.of Figure s4 are 'xeiL it Will'be seen that the outer pair of `disks may be independently :and am'ally moved `relative thereto so as to widen or :constrictthe Widths of the peripheral grooves of the rotors as desired, the nuts `8!) being thereafter tightened against the collars Bi' so to lock the outer disks in their adjusted positions. Inadditiom one of each pair 'of shafts 5t is adjustable toward or from the other of the shafts, this 'being accomplished by Ymaking one set of bearings 57 slideable 'ina manner wellknown in the art. The provision of these two vadjustmentsperirnits the positioning vof the "fingers 63, as shown in -Figurefd at Vselected points along two angularly related lines of movement thus permitting enlargement or constriction of the aperture B4.

Means is provided for moving vone .disk of the rotor relative to the other disk thereof 'so as to successively compress and expandthe 'peripheral groove of the rotor and means's further provided, operative upon rotary motion of the rotor, for eiiecting the aforesaid relative-movement of the disks. Referring to 'Figure 4, it will be seen that the confronting hubs '59 the centerpair of disks 58, which incidently are vcapable of sliding motion 'axially of the shaft 5t, are secured together by a push rod Si, engaged in aligned threaded holes 'io'rmed'in the'hucs and extending slideably through clearance apertures provided inthe hub of an outer disk and in its associated 'collar 8T. Stops 'H2 'pinned 'to Athe push rod and disposed Aon each side of the collar '8l vserve to'limit reciprocations ofthe center disks along the'shaft 55. The extreme outer end of the push rod 9i bears against an annular cam, best shown inFigures 7 and 8, provided 4with alternate depressions 93 yand protuberances et, and a ycoil spring "95, interposed Vbetween the disk hub carrying the inner end of the push rod and the confronting face ofthe adjacent disk hub, serves tomainta'in pressure of the push 'rod against the cam. AThe cam may 1be mounted on any convenient 'xed As the shaft "56 is rotated, the end of the push rod 'Bl is caused totraverse thesuc'cessive depressions '93 and protuberan'ces 'Stof the cam thus urging the center disks lof the rotor through repeated cycles of motion axially Aof the shaft, the spring '95 functioning to 'eiect recovery movement ofthe disks during one-half lof each operating cycle. 4The purpose `forrnovingthe center .disksiis'to effect a plurality of rapidly successive contractions 4and expansions of the rotor `grooves during v-each Yrevolution thereof and, consequently, 4to cause like variations in the'sizeo the'apertur'es 61S. Thus, not only is therange of nut sizes Whichthe rotor unit is 'oapable'ofoperating upon extended vabove and fbelow a `normal 'predetermined size, but a crush-ing pressure `which is `angularlyrelated to the radialfcrrushing pressure imposed on the nuts by the rotors is obtained. This secondary Apressure 'si-nce it is imposed in a direction paralleling the shaft 56 may be aptly termed axial stress as Ydietinguished from the radial -'stressmen tioned above.

the-preceding description it has been shown how the-nutsare Yfed into the-uppermost cracker unit'end'how the shelis of selected nutszare rup- After :being upon icy the rotors uppermost unit the ,discharge Yfrom ythrougli the .opening dit will consist lof lar-gepr smaller particles :of 'nut meat, crushed shells and whole nuts' which :are suiicientiysmall as" to pass the rotors without being acted thereon. Mea-ns is provided for separating the ruptured nuts fromthe whole ones and for conveying the latter toward and into the next succeeding cracker unit. Located below the discharge openings 54 of the upper and intermediate cracker units, is a combined screen, shell remover and conveyor comprising a plurality of spaced elongated rollers 95, which are spaced apart, as is shown in Figure 3, so as to provide slots 91 between adjacent pairs of the rollers, and which are jcurnaled in bearings B8 mounted on the framework 9. Each of the rollers of a set are connected together for synchronous rotation by suitable means, such as the gears 99 of Figure 3, and one roller of each set is provided. with a grooved pulley IBI which is engaged by a belt Iilz operating from a pulley 03 carried by a shaft IM suitably journaled in an elevated position on the framework. Bevel gearing |06 connects the shaft led to be powered from a jackshaft IEP! which in turn is connected for rotation with the shaft 6B by means of pulleys Hi8 and a belt ERS. Each set of rollers 95 is angularly inclined from a position just below the discharge opening of the upper cracker unit toward a position over the hopper 5I of the next lower cracker unit. As the aforesaid flow of whole nuts, nut meats and shell particles emerges from the discharge opening 54 of the uppermost cracker unit, it will fall onto the subtendent rollers 9B. The shell and meat particles which are small enough will immediately drop through the slots 2'! and will be guided by the inclined wall III downwardly and onto a collector or belt H2, positioned below the lowermost cracker unit, which carries the material in a path traversing and below the suction hood H3 of a blower H4 which serves to separate the shell particles and other inedible brous material from the nut meat, the latter then passing along the belt toward a sorting m: packing table not shown. The belt H2 which is mounted on pulleys I 6 Aiournaled in bearings l Il. may be powered by any suitable drive means such as a chain H8.

In the now oi material from the uppermost cracker unit there may be, in addition to the uncracked smaller size nuts, a certain quantity of nuts whose shells have been ruptured yet which are too large to pass freely through the slots 91 between the rollers 96. The action of the rotating rollers, on nuts in this condition is to tend to draw the nut into the grooves thereby eecting a squeezing which loosens and separates any cracked shell still clinging to the nut meat and, usually, to break the whole nut meat into two halves thus releasing the brous membrane Vpresent between the halves. The material may then fall through the slots 9i and pass downwardly to the conveyer belt H2. The uncracked nuts which were too small to be acted upon by the previous rotors will roll along in the grooves formed by adjacent pairs of rollers, the rolling being eiected partially by gravity and partially as a result of the roller rotation, and will finally pass from the lower end of the roller unit and fall into the hopper of the next lower cracker unit wherein it may or may not be acted upon by the rotors depending upon its size. The spacing between the rollers 96 which provides the slots 31 is suiciently small that the smallest size of nut normally encountered will not fall through the slots of any oi the upper units but will be carried through each cracker unit and along the intervening roller units until it is deposited into the hopper of the nal cracker unit, which is designed to receive the smaller sizes of nuts. It will also be noted that the lower end of each roller 86 terminates in a shaft of materially reduced diameter. This provides a pronounced widening of the slots immediately above the hoppers 5| so as to provide free passage for the nuts dropping into the hoppers.

The foregoing description of the appartus of my invention covers the complete series of operations occuring from the time that the nuts are deposited in the receiving hopper l2 until the meats are passed from the apparatus on the conveyer belt H2. It will be seen that from the start of the-process to the completion thereof the nuts are handled in a gentle manner which is highly conducive to the production of a maximum percentage of commercially desirable nut meat halves, and the likelihood of shell splinters and for other fibrous waste being forcibly embedded in the meats is reduced to an absolute minimum. The main reason for this lies in the particular construction of rotors employed for cracking the shells, the resilient fingers with which the rotors are equipped serving to efciently crack but not shatter the shell and the addition of a secondary side or axial pressure serving to further enhance the shell cracking action.

I claim:

l. In apparatus of the character described, a cracking unit having therein charging and discharge openings through which a ilow of nuts may be passed, respectively, into and from the cracking unit, means in said cracking unit and interposed in the path of flow of nuts therethrough for selecting certain of the nuts from said ilow and for rupturing said nuts while rejecting other of the nuts, said selecting and rupturing means comprising four relatively exiblc rotating elements, means to rotate said elements in directions substantially paralleling said flow of nuts and providing at the peripheries thereof and within the path of said flow an aperture of substantially circular cross-section through which said nuts may pass, and means for reciprocating at least two of said elements axially relative to each other so as to periodically vary the size of said aperture.

2. In apparatus of the character described, a cracking unitl having therein charging and discharge openings through which a ilow of nuts maybe passed respectively inte and from the cracking unit, a pair ci substantially parallel. spaced shafts mounted for rotary movement in said cracking unt, each of said shafts having thereon a rotor comprising at least a pair of4 axially spaced disks each of said disks beingA provided with integral spaced portions partially sheared from the body or" the disk and arcuately shaped to form, in conjunction with the similar partially sheared portions of the other axially confronting disk, a peripheral groove in the rotorA of substantially semi-circular form, the peripheral grooves of the respective rotors being in registry transaxially and cooperating, in the plane of tangency of the rotors, to forma substantially` circular aperture disposed in the path of ilow of said nuts and through which successive nuts in said flow may be passed, means for imparting rotary movement to said shafts, and means for.

may be passed respectively into and from the cracking unit, a pair of substantially parallel spaced shafts mounted for rotary movement in said cracking unit, each of said shafts having thereon a rotor comprising at least a pair of axially spaced disks each of said disks being provided with integral spaced portions partially sheared from the body of the disk and arcuately shaped to form, in conjunction with the similar partially sheared portions of the other axially confronting disk, a peripheral groove in the rotor of substantially semi-circular form, the peripheral grooves of the respective rotors being in registry transaxially and cooperating, in the plane of tangency of the rotors, to form a substantially circular aperture disposed in the path of flow of said nuts and through Which successive nuts in said flow may be passed, at least one disk on each rotor being fixed against movement axially of the shaft and another disk on each shaft being movable axially of the shaft, means for imparting rotary movement to said shafts, and means for moving said movable disk successively, toward and from said fixed disk.

4. In apparatus of the character described, a cracking unit having therein charging and discharge openings through which a flow of nuts may be passed respectively into and from said cracking unit, bearings mounted in said cracking unit, a pair of substantially parallel spaced shafts journaled in said bearings, each of said shafts having thereon a rotor comprising at least a pair of axially spaced disks, each of said disks having integral spaced portions thereof partially sheared therefrom and arcuately shaped to form, in conjunction with similar partially sheared portions of the other axially confronting disk, a peripheral groove in the rotor of substantially semicircular cross-sectional form, the peripheral grooves of the respective rotors being in co-planar registry transaxially of the rotors and cooperating, in the plane of tangency of the rotors, to form a substantially circular aperture disposed in the path of flow of said nuts and through which successive nuts in said flow may be passed, one of said disks being fixed against movement axially of said shaft and another of said disks confronting the fixed disk being shiftable axially of the shaft, a cam carried by one of said bearings concentric vvith said shaft and having thereon undulations and depressions paralleling the axis of the shaft, means for imparting rotary movement to said shafts, and a push rod engaged respectively with said shiftable disk and said cam for shifting the latter disk on the shaft during rotary movement of the shaft.

FREDERICK M. BALDWIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,260,203 Kammerdiener Mar. 19, 1918 1,282,408 Gaylord et a1 Oct. 22, 1918 1,388,574 Kelling Aug. 23, 1921 1,469,332 Gotzheim Oct. 2, 1923 1,477,649 Huston Dec. 18, 1923 1,971,170 Baldwin Aug. 21, 1934 2,144,841 Glaser Jan. 24, 1939 2,205,177 Schlegel June 18, 1940 2,220,320 Dragon Nov. 5, 1940 2,319,757 Vigneau May 18, 1943 2,343,270 Agnew Mar. 7, 1944 FOREIGN PATENTS Number Country Date 417,176 France Aug. 23, 1910 16,829 Great Britain July 22, 1913 

